$(function (){
	var scrolltotop={
			setting:{
				startline:100, //起始行
				scrollto:0, //滚动到指定位置
				scrollduration:400, //滚动过渡时间
				fadeduration:[500,100] //淡出淡现消失
			},
			controlHTML:'<img src="/LifeService/jsp/front/images/top.png" style="width:30px; height:30px; border:0;" />', //返回顶部按钮
			controlattrs:{offsetx:10,offsety:10},//返回按钮固定位置
			anchorkeyword:"#top",
			state:{
				isvisible:false,
				shouldvisible:false
			},scrollup:function(){
				if(!this.cssfixedsupport){
					this.$control.css({opacity:0});
				}
				var dest=isNaN(this.setting.scrollto)?this.setting.scrollto:parseInt(this.setting.scrollto);
				if(typeof dest=="string"&&jQuery("#"+dest).length==1){
					dest=jQuery("#"+dest).offset().top;
				}else{
					dest=0;
				}
				this.$body.animate({scrollTop:dest},this.setting.scrollduration);
			},keepfixed:function(){
				var $window=jQuery(window);
				var controlx=$window.scrollLeft()+$window.width()-this.$control.width()-this.controlattrs.offsetx;
				var controly=$window.scrollTop()+$window.height()-this.$control.height()-this.controlattrs.offsety;
				this.$control.css({left:controlx+"px",top:controly+"px"});
			},togglecontrol:function(){
				var scrolltop=jQuery(window).scrollTop();
				if(!this.cssfixedsupport){
					this.keepfixed();
				}
				this.state.shouldvisible=(scrolltop>=this.setting.startline)?true:false;
				if(this.state.shouldvisible&&!this.state.isvisible){
					this.$control.stop().animate({opacity:1},this.setting.fadeduration[0]);
					this.state.isvisible=true;
				}else{
					if(this.state.shouldvisible==false&&this.state.isvisible){
						this.$control.stop().animate({opacity:0},this.setting.fadeduration[1]);
						this.state.isvisible=false;
					}
				}
			},init:function(){
				jQuery(document).ready(function($){
					var mainobj=scrolltotop;
					var iebrws=document.all;
					mainobj.cssfixedsupport=!iebrws||iebrws&&document.compatMode=="CSS1Compat"&&window.XMLHttpRequest;
					mainobj.$body=(window.opera)?(document.compatMode=="CSS1Compat"?$("html"):$("body")):$("html,body");
					mainobj.$control=$('<div id="topcontrol" >'+mainobj.controlHTML+"</div>").css({position:mainobj.cssfixedsupport?"fixed":"absolute",bottom:mainobj.controlattrs.offsety,right:mainobj.controlattrs.offsetx,opacity:0,cursor:"pointer"}).attr({title:"返回顶部"}).click(function(){mainobj.scrollup();return false;}).appendTo("body");if(document.all&&!window.XMLHttpRequest&&mainobj.$control.text()!=""){mainobj.$control.css({width:mainobj.$control.width()});}mainobj.togglecontrol();
					$('a[href="'+mainobj.anchorkeyword+'"]').click(function(){mainobj.scrollup();return false;});
					$(window).bind("scroll resize",function(e){mainobj.togglecontrol();});
				});
			}
		};
		scrolltotop.init();
});